There has been known an automatic transmission that includes a manual valve driven according to an operation of a select lever at an oil passage, and the oil passage couples a hydraulic pressure supply source and a plurality of forward movement friction elements. Such automatic transmission possibly causes a mismatch of a range (hereinafter referred to as a pseudo D) where a driving position of the manual valve is not at a traveling range position even if a signal from an inhibitor switch, which detects a selected range, is a signal for traveling range.
In this case, since the driving position of the manual valve is not at the traveling range position, a hydraulic pressure is not supplied to the friction element requiring an engagement for forward movement. However, even in this case, a hydraulic pressure control according to the traveling range is executed on the basis of the signal from the inhibitor switch. This results in a difference between a hydraulic pressure instruction value to engage the friction element and an actual hydraulic pressure.
Driving the manual valve to an appropriate position, namely, the traveling range position, with the difference between the hydraulic pressure instruction value and the actual hydraulic pressure rapidly increases the actual hydraulic pressure so as to be the hydraulic pressure instruction value. The rapid engagement of the friction element results in providing an evil shock to a driver.
JP2009-221986A discloses a technique that restricts an output from an engine when a pseudo D state continues for a predetermined time, and the output is input to a transmission.